I know lots of iPhone 3GS user still in 3.1.3 and worried about their iPhone. Good news is now you could JailBreak & Unlock iPhone 3GS easily but you should choose tools carefully as if you picked wrong tool you might lose any chance for future update too.
Yes Its true, like if you use SpiritJB then you can’t upgrade to iOS 4.0, as all iOS 4.0 JailBreak tools does not work with that. Another important thing all iPhone 3GS tools only work with previously jailBroken iPhone and best if you have blobs saved in cydia.
Here is how to JailBreak & Unlock iPhone 3GS on Firmware 3.1.3 and UpGrade to iOS 4.0 with Unlock
3. Now follow this guide to JailBreak iPhone 3GS on 3.1.3 or 3.1.2. It will JailBreak Your iPhone 3GS on 3.1.3 or 3.1.2 safely.
4. Now Its time for Unlock. Follow this Guide to Unlock iPhone 3GS on 3.1.3 or 3.1.2 with Baseband 05.12.01.
5. Now you have completely working Unlocked iPhone 3GS on 3.1.3 or 3.1.2. If you want to upgrade to iOS 4.0 then follow the process below or you are happy with this 3.1.3 then you could ignore rest of the post.
7. Now JailBreak your iPhone 3GS on iOS 4.0
If you are on Windows follow this Guide using Sn0wbreeze
if you are on Mac use this Guide using Pwnage Tool
8. Now again time for unlock . Follow this Guide to Unlock iPhone 3GS on 3.1.3 or 3.1.2 with Baseband 05.12.01 once again.
Note: if you accidentally upgraded to iOS 4.0, then you need to downgrade first following this tool. Unless you can’t JailBreak or Unlock.
Few important thing keep in mind while JailBreaking iPhone – entering DFU mode correctly is very important. Read this post of How to Put iPhone into DFU mode and difference between DFU mode and recovery Mode.
You could always get support from UnlockAlliPhone.com about any Unlock & JailBreak issue of any model of iPhone including iPhone 2G,3G & 3GS and also upcoming iPhone 4. They provide Premium Members Support for life time. Means just pay one time a small fee and you will receive support(real human support – avg response time 2 hour) for all present & future version of iPhone.